The present invention relates generally to a heat dissipating component and, more particularly, to a separable hybrid cold plate and heat sink for use with an electronic device.
The removal of heat from electronic components is a problem continuously faced by electronic packaging engineers. As electronic components have become smaller and more densely packed on integrated boards and chips, designers and manufacturers now are faced with the challenge of how to dissipate the heat generated by these components. It is well known that many electronic components, especially semiconductor components such as transistors and microprocessors, are more prone to failure or malfunction at high temperatures. Thus, the ability to dissipate heat often is a limiting factor on the performance of the component.
Electronic components within integrated circuits have been traditionally cooled via forced or natural convective circulation of air within the housing of the device. In this regard, cooling fins have been provided as an integral part of the component package or as separately attached elements thereto for increasing the surface area of the package exposed to convectively-developed air currents. Electric fans have also been employed to increase the volumetric flow rate of air circulated within the housing. For high power circuits (as well as smaller, more densely packed circuits of presently existing designs), however, simple air circulation often has been found to be insufficient to adequately cool the circuit components.
It is also well known that heat dissipation, beyond that which is attainable by simple air circulation, may be effected by the direct mounting of the electronic component to a thermal dissipation member such as a xe2x80x9ccold platexe2x80x9d, evaporator, or other heat sink.
There are applications where cold plates or evaporators are used for the lower temperatures they can deliver, but space or cost considerations prevent full redundancy or backup cooling means. In these applications, an air cooled heat sink may provide sufficient redundancy for temporary higher temperature usage.
In such xe2x80x9chybridxe2x80x9d cooling applications it is advantageous to thermally isolate the heat sink from the cold plate/evaporator during normal usage to reduce ambient heatflow into the cold plate/evaporator. For example, if the heat sink is thermally in close contact with the cold plate when the cold plate is providing the primary means of cooling, the heat sink dumps considerable ambient heat into the cold plate as the cold plate literally chills the air between the heat sink fins thereby producing undesirable condensation.
Thus, a more efficient cooling system is desired when the cold plate between the heat sink and the module being cooled is functioning or providing the primary cooling of the module.
This disclosure presents an apparatus and method for cooling an electronic module that includes coupling a heat sink in thermal contact to the electronic module via a cap defining one end of the electronic module forming an assembly. A fastener configured to clamp the heat sink to the electronic module is torqued down to apply a first clamping force between the heat sink and the electronic module at a reference temperature. The fastener is configured to apply a second clamping force between the heat sink and the electronic module in direct proportion to a temperature change of the assembly relative to the reference temperature.
In another embodiment, an apparatus and method for automatic thermal switching of the individual components of a cooling unit for electronics applications is disclosed. The hybrid cooling unit removes heat from a module primarily via a liquid coolant system having circulating coolant and includes a heat sink in separable thermal contact therewith, a fastener coupling the heat sink to the cold plate acts as an automatic thermal switch to alter the clamping force between the heat sink and cold plate. In this manner, the clamping force therebetween is high when the cold plate is not functioning and is lowered when the cold plate is providing the primary cooling means to a module coupled to the cold plate.